Investigating the Characteristics of Wet Shotcrete Pipeline Transportation

Lianjun Chen,Jiahao Sun,Xiaohan Guo,Nan Guo,Yanan Huang,Guoming Liu 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12

In order to study the resistance characteristics of wet shotcrete pipeline transportation, a small pipe type rheology and resistance test device was developed. The device is used for straight pipe resistance test, pump stop test and dyed concrete test were carried out on concrete with different characteristics. The fluidity changes of concrete with different characteristics were obtained through experiments. The results show that the slump, pressure bleeding rate, water-cement ratio were all negatively related to pipeline transportation resistance. The influence of the three factors on resistance was in order: pressure bleeding rate, water-cement ratio, slump. The dyed concrete test confirmed the principle of the plunger flow in the pipeline when concrete is pumped. The thickness of the lubricating layer increased with the increase of the water-cement ratio. The concrete pipeline transportation resistance increased with the increase of the standing time. The fitting curve was obtained through the correlation analysis between resistance and lubricating layer thickness, and the two were negatively correlated. This provides a new research idea for the study of drag reduction measures for concrete pipeline transportation.

Performance improvement prediction of push chain moist-mix concrete spraying machine employing orifice plate

Lianjun Chen,Hui Ma,Guanguo Ma,Gang Pan,Pengcheng Li,Zhenjiao Sun 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

Push chain moist-mix concrete spraying machine is widely used in shotcrete construction processes, but shotcrete surplus has always been the main problem affecting work efficiency. To improve the efficiency, the orifice plate is employed in the discharge cylinder, considering three different distributions (equal, left concentrated and both side distribution) of the holes and two hole diameters (6 mm and 8 mm). In different orifice plate, the discharge cylinder flow field is studied employing the FLUENT software by the computational fluid dynamic method. Besides, dimensionless evaluation index of the discharge cylinder flow field is defined based on the force of particles. By comparing dimensionless index and velocity vector, the best orifice plate (both side distribution and 8 mm) is presented. Compared without orifice plate, the experiment showed the shotcrete surplus ability is reduced by 26 %-87 %. This study provides guidance for the design and optimization of pneumatic conveying equipment.

Differential die-away technology applied to detect special nuclear materials

Lianjun Zhang,Mengjiao Tang,Chen Zhang,Yulai Zheng,Yong Li,Chao Liu,Qiang Wang,Guobao Wang Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

Differential die-away analysis (DDAA) technology is a special nuclear material (SNM) active detection analysis technology. Be a nuclear material shielded or not, the technology can reveal the existence of nuclear materials by inducing fission from an external pulsed neutron source. In this paper, a detection model based on DDAA analysis technology was established by geant4 Monte Carlo simulation software, and the optimal sensitivity of the detection system is achieved by optimizing different configurations. After the geant4 simulation and optimization, a prototype was established, and experimental research was carried out. The result shows that the prototype can detect 200 g of ²³⁵U in a steel cylinder shield that's of 1.5 cm in inner diameter, 10 cm in thickness and 280 kg in weight.

Pulmonary Actinomycosis Imitating Lung Cancer on 18F-FDG PET/CT: A Case Report and Literature Review

Lin Qiu,Lianjun Lan,Yue Feng,Zhanwen Huang,Yue Chen 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.6

Here we report a case of 41-year-old man with a soft tissue density mass at right upper lung and palpable abscesses at right upper backside and right wrist. 18F-fluorodeoxyglucose positron emission tomography/computed tomography demonstrated a 7.8 x 5.0 cm mass with soft-tissue density in the upper lobe of the right lung with high metabolic activity. The infiltrative mass extended to adjacent chest wall soft tissue. Final diagnosis of pulmonary actinomycosis with multiple abscesses was made. The patient responded well to antibiotics treatment.

Advanced Gastric Cancer and Perfusion Imaging Using a Multidetector Row Computed Tomography: Correlation with Prognostic Determinants

Huan Zhang,Zilai Pan,Lianjun Du,Chao Yan,Bei Ding,Qi Song,Huawei Ling,Kemin Chen 대한영상의학회 2008 Korean Journal of Radiology Vol.9 No.2

Objective: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. Materials and Methods: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti- CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student’s t-test and the Spearman rank correlation were performed in SPSS 11.5. Results: The mean perfusion values and MVD for tumors were as follows: BF (48.14 16.46 ml/100 g/min), BV (6.70 2.95 ml/100 g), MTT (11.75 4.02 s), PS (14.17 5.23 ml/100 g/min) and MVD (41.7 11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). Conclusion: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer. Objective: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. Materials and Methods: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti- CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student’s t-test and the Spearman rank correlation were performed in SPSS 11.5. Results: The mean perfusion values and MVD for tumors were as follows: BF (48.14 16.46 ml/100 g/min), BV (6.70 2.95 ml/100 g), MTT (11.75 4.02 s), PS (14.17 5.23 ml/100 g/min) and MVD (41.7 11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). Conclusion: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer.

Efficiency calculation of the ⁿMCP with ¹⁰B doping based on mathematical models

Yang, Jianqing,Zhou, Jianrong,Zhang, Lianjun,Tan, Jinhao,Jiang, Xingfen,Zhou, Jianjin,Zhou, Xiaojuan,Hou, Linjun,Song, Yushou,Sun, XinLi,Zhang, Quanhu,Sun, Zhijia,Chen, Yuanbo Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

The ⁿMCP (Neutron sensitive microchannel plate) combined with advanced readout electronics is widely used in energy selective neutron imaging because of its good spatial and timing resolution. Neutron detection efficiency is a crucial parameter for the ⁿMCP. In this paper, a mathematical model based on the oblique cylindrical channel and elliptical pore was established to calculate the neutron absorption probability, the escape probability of charged particles and overall detection efficiency of ⁿMCP and analyze the effects of neutron incident position, pore diameter, wall thickness and bias angle. It was shown that when the doping concentration of the ⁿMCP was 10 mol%, the thickness of ⁿMCP was 0.6 mm, the detection efficiency could reach maximum value, about 24% for thermal neutrons if the pore diameter was 6 ㎛, the wall thickness was 2 ㎛ and the bias angle was 3 or 6°. The calculated results are of great significance for evaluating the detection efficiency of the ⁿMCP. In a subsequent companion paper, the mathematical model would be extended to the case of the spatial resolution and detection efficiency optimization of the coating ⁿMCP.